I. "A liturgist in the sanctuary": Worship as the chief end of GodWorship is the inner and outer life of God (Rev. 4-5)
The end (telos) of all right action is the love of God (1 Cor. 13)The worker of worship (leiturgeos, Heb. 8:2) is the Triune God (9:1, 9:11-14)
Sin, or concupiscence, is "wrongly directed love" (idolatry)All healthy worship practices (not just altar calls!) express and accomplish God's missionIsrael is God's worshiping people (Deut. 6; Amos 5:21-24; Matt. 5:14-16, 6:1-18)Jesus is the ultimate subject and object of worship (Heb. 5:7-10, 7:26-28)Worship is God-directed, Christ-shaped, Spirit-driven (Acts 2) ...

... drawing us into the communion between Son and Father (John 17)
... drawing us into the communion of Christ and his body (1 Cor. 12)
... drawing us into the communion of saints (Rom. 12)
... commissioning us as agents of the Kingdom's growing communion (Matt. 28)

James B. Torrance's three models of worship/mission (two of them defective):

Missionary of the Good News (Matt. 10:2)
Bringer of the Kingdom of God: a new, holy, public order (Matt. 10:7-8)
Witness to the resurrection (Acts 1:26)
Head of Israel (Rev. 21:14)
Foundation of the Church (Eph. 2:20)

So apostolicity names the later Church's fidelity to its irreplaceable foundations
Apostolicity describes the Church's center and its expanding boundaries
Apostolicity discerns deep continuity with the original witnesses and the eschatological frontier